| Abstract: | Devices for measuring single cell changes in photosynthetic efficiency in
algal aquaculture are disclosed that include a combination of modulated
LED trans-illumination of different intensities with synchronized through
objective laser illumination and confocal detection. Synchronization and
intensity modulation of a dual illumination scheme were provided using a
custom microcontroller for a laser beam block and constant current LED
driver. Therefore, single whole cell photosynthetic efficiency, and
subcellular (diffraction limited) photosynthetic efficiency measurement
modes are permitted. Wide field rapid light scanning actinic illumination
is provided for both by an intensity modulated 470 nm LED. For the whole
cell photosynthetic efficiency measurement, the same LED provides
saturating pulses for generating photosynthetic induction curves. For the
subcellular photosynthetic efficiency measurement, a switched through
objective 488 nm laser provides saturating pulses for generating
photosynthetic induction curves. A second near IR LED is employed to
generate dark adapted states in the system under study. |